Structured targets for detection of Megatesla-level magnetic fields through Faraday rotation of XFEL beams
Structured targets for detection of Megatesla-level magnetic fields through Faraday rotation of XFEL beams
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DOI：
10.1063/1.5066109
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发表时间：
2018-09
影响因子：
2.2
通讯作者：
Tao Wang;T. Toncian;M. Wei;A. Arefiev
中科院分区：
文献类型：
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作者：
Tao Wang;T. Toncian;M. Wei;A. Arefiev
被高强度激光脉冲照射的固体密度目标可以变得相对透明，从而使其能够维持极强的激光驱动的纵向电子电流。电流产生具有缓慢变化的mt级方位磁场的灯丝，该磁场已被证明能够以多种应用所需的准直光束的形式促进多mev光子的有效发射。本文研究了利用欧洲x射线自由电子激光器的x射线束通过法拉第旋转探测磁场的可行性。后处理的三维细胞内粒子模拟表明，尽管相对透明极大地减少了均匀目标中的旋转，但通过采用包含通道的结构化目标来实现10−4 rad的旋转角度，可以成功地逆转这种有害影响。通道必须是相对透明的，电子密度低于体中的近固体密度。通过改变通道半径和聚焦驱动磁场的激光脉冲，优化了探测装置。我们预测，法拉第旋转可以产生103个光子，其偏振与入射的100 fs长探测光束的偏振正交，该光束具有5 × 1012个x射线光子。根据计算的旋转角度，极化纯度必须远高于10−8，才能检测到噪声级以上的信号。被高强度激光脉冲照射的固体密度目标可以变得相对透明，从而使其能够维持极强的激光驱动的纵向电子电流。电流产生具有缓慢变化的mt级方位磁场的灯丝，该磁场已被证明能够以多种应用所需的准直光束的形式促进多mev光子的有效发射。本文研究了利用欧洲x射线自由电子激光器的x射线束通过法拉第旋转探测磁场的可行性。后处理的三维细胞内粒子模拟表明，尽管相对透明极大地减少了均匀目标中的旋转，但通过采用包含通道的结构化目标来实现10−4 rad的旋转角，可以成功地逆转这种有害影响。通道必须是相对透明的，电子密度低于近30°c。
A solid density target irradiated by a high-intensity laser pulse can become relativistically transparent, which then allows it to sustain an extremely strong laser-driven longitudinal electron current. The current generates a filament with a slowly varying MT-level azimuthal magnetic field that has been shown to prompt efficient emission of multi-MeV photons in the form of a collimated beam required for multiple applications. This work examines the feasibility of using an x-ray beam from the European x-ray free electron laser for the detection of the magnetic field via the Faraday rotation. Post-processed three dimensional particle-in-cell simulations show that, even though the relativistic transparency dramatically reduces the rotation in a uniform target, the detrimental effect can be successfully reversed by employing a structured target containing a channel to achieve a rotation angle of 10−4 rad. The channel must be relativistically transparent with an electron density that is lower than the near-solid density in the bulk. The detection setup has been optimized by varying the channel radius and focusing the laser pulse driving the magnetic field. We predict that the Faraday rotation can produce 103 photons with polarization orthogonal to the polarization of the incoming 100 fs long probe beam with 5 × 1012 x-ray photons. Based on the calculated rotation angle, the polarization purity must be much better than 10−8 in order to detect the signal above the noise level.A solid density target irradiated by a high-intensity laser pulse can become relativistically transparent, which then allows it to sustain an extremely strong laser-driven longitudinal electron current. The current generates a filament with a slowly varying MT-level azimuthal magnetic field that has been shown to prompt efficient emission of multi-MeV photons in the form of a collimated beam required for multiple applications. This work examines the feasibility of using an x-ray beam from the European x-ray free electron laser for the detection of the magnetic field via the Faraday rotation. Post-processed three dimensional particle-in-cell simulations show that, even though the relativistic transparency dramatically reduces the rotation in a uniform target, the detrimental effect can be successfully reversed by employing a structured target containing a channel to achieve a rotation angle of 10−4 rad. The channel must be relativistically transparent with an electron density that is lower than the near-so...